Injectors

[Rawze]

If you haven't read this, you should. It may be related ...

http://rawze.com/forums/showthread.php?t...77#pid2277


Injectors themselves typically don't "decide" what particular RPM range they are going to act up in normally. It sounds more like other problems like timing issues from what you have just described. Injectors alone? -- Very very unlikely, but not completely impossible.


Someone describing moderate to heavy vibration in an ISX engine in the 1300 - 1500 RPM range, if it is confirmed in the engine itself, is usually almost always too low of final crank angle in the engine.

Too low of a final crank angle typically results in excess cylinder pressures with less power gains vs fueling applied, excess internal vibration in the 1300 - 1500 RPM range, and the hammering of the crankshaft bearings, eventually leading to excess bearing wear and/or engine destruction.

Crankshaft vibration is damaging to the crank bearings at the very least. Here is an extreme example of one that was the result of typical bad ECM programming. It was from one of those big-name places that advertises heavily, is expensive, and promotes themselves at all the truck shows. it was one of those places that offer after-market non-vg turbocharger retrofits, and all kinds of other engine damaging/wasteful modifications. This pic is of one of the crank bearings after a couple hundred thousand miles of a bad program. It failed, throwing a piston through the side of the block with no warning.





Some of the typical causes of this can be ANY of these ...


* A Bad delete!- A delete that has programming resulting in too low of final crank angles. ALL of the big-name deletes do this, and anyone who has put a copy-cat of one in your ECM will have the same problems too. 99.7% of all deletes I have even seen for ISX engines are bad and have the potential to cause these same issues along with many others.

* The wrong program in your engine. Someone put in a different ECM program in an attempt to "up" the hp rating, and it is not 100% compatible. this happens very very often, because the CPL number and other data as seen by Insite/Incal is NOT enough information to do this correctly. Here is more info on that ...
http://rawze.com/forums/showthread.php?tid=1

* Bad static timing. The static timing has slipped, or is NOT adjusted according to your engine serial number. CM870 engines have DIFFERENT static timing settings based specifically on engine serial number, unlike newer model ISX engines.

* Bad/worn out timing/metering actuators, causing timing issues and problems.

* Overboosting for the fuel flow that is being supplied. This creates excess cylinder pressures, detonation, and crank angle issues with little to no power gains.

* Seriously worn down crank bearings due to previous problems with hammering, etc.

* (low likeness) Something mucking up your timing and/or final crank angles, like sensors reading very very badly, but perhaps not failed yet, like exhaust BP sensor, or ambient temp or altitude sensor, etc.

* Incorrectly reading fuel pressure or temp sensor, or one of those dammed P.O.S. devices that fool your fuel sensors like the "PowerBox" or "HP" increasing fuel-system pressure fooling devices. They do nothing but f##k up the fuel pressure sensor feedback data and hammer out crank bearings in attempt to get a few more HP. Very bad for engine.

* Excess injector cam vibration due to spun and/or completely worn down injector cam bearings in the head.

* A bent piston rod, or unbalanced crank itself.

* Air compressor is not timed correctly. Vibration from this is usually is subtle though.

* crank shaft damper is bad. Vibration from this is usually is subtle though.

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Does not matter WHAT is causing it -- If it is vibration due to too low of final crank angles, and/or moderate, and you are driving it -- Eventually your crank bearings will get excess play in them by being hammered on, and you will eventually destroy the engine by sending a piston through the block with zero warning. Regular inspection of crank shaft bearings is required, and you should be able to see differences in wear patterns on them to help determine where the vibration is coming from if it is cylinder/piston rod related.

ALSO, you said that your turbo is running very cool. -- If it is running that cool, and it is not normal for that make and model of truck, there could be something wrong. -- Symptoms of detonation/timing issues can also cause lower than normal exhaust manifold temps, especially considering you only have 32-psi of boost. Normally, low boost levels results in higher than normal manifold temps, not lower.

You also said your master plan is to run it to 1.2 million miles. -- I hope you were kidding right? -- That is a pipe dream when considering what you are describing. -- You are better off playing the pick-3 lottery. Your luck WILL run out!. -- You know you have a completely worn out head by now, worn out actuators, injectors, higher than normal crank case pressure, excess engine vibration, etc. From what you describe, it likely still has the original rod/main bearings in it too. That makes it a time bomb waiting to send a piston through the block with no warning. ISX is common for this when no one changes bottom end bearings after 800k+ miles on them.

DO THE RIGHT THING!. And STOP fooling yourself. -- Start planning on replacing that worn-out head soon,,.. AND inframe it while you have it apart!. If you wanted the bottom end to last to 1.2, 14. , or 1.6 million,.. SOMEONE should have replaced that head back when it had 700-800k miles on it. NOW, it is too late!.


For those who buy used trucks with 700+k miles on them or more -- You can't buy a truck with that many miles on it and not expect to have to do an overhaul of the engine shortly after. --- THAT WOULD BE BAD PLANNING!.